Baby Jay Steven, 8lb 5oz in imperial measures, arrived to the delight of his dad and mum Leigh.

The trader took time out from his market stall to be present at the birth at Sunderland Royal Hospital.

Mr Thoburn, 37, who has two other children, said: "I'm glad of the distraction after all that's happened. I think I'm better at being the provider rather than the nappy-changer, but I'll be taking my turn."

Mr Thoburn was found guilty of selling bananas by the pound from his Sunderland market stall in contravention of European law.

He appealed against his conviction at the High Court but judges rejected his claim that domestic law provided a loophole which meant EU directives requiring goods to be sold in metric units did not apply in England and Wales.

He was one of four traders who are continuing their battle and have lodged a petition to seek leave to appeal to the House of Lords to have their convictions overturned.

Neil Herron, for the Metric Martyrs' Defence Fund, said: "Even Tony and Cherie Blair announced the arrival of baby Leo in pounds and ounces. It highlights the absurdity of the criminalising of honest, hard-working men for using a system of measurement we all understand."